There were a lot of… lets just call ’em optimistic Android users out there PO’d to find that — contrary to rumors — Google’s all new messaging service, Google+ Hangouts, didn’t do much to unify anything. Sure, now you can send picture messages through Google Talk Hangouts, but with Google+ messages still being sent through Google+ Messenger, not to mention SMS messages still being handled by the native text messaging app — just what the heck did Google unify? Slow down there, guys. At least one of those issues is being addressed in the very near future.
Googler Ben Eidelson explains on Google+ page today that, yes, Google will soon give the axe to Google+ Messenger, to be replaced by none other than Hangouts. Right now, Google is busy doing some work on the backend to make sure everything is backed up and that the transition will be an easy one. After that, expect that red Messenger icon to forward you straight to Hangouts before eventually going the way of the dinosaur. Hope this helps answer many of your questions regarding Google+ Messenger.